I. Field of the Invention
This invention relates generally to fueling valves and couplings used in the dispensing or loading of gasoline, butane, propane, other fuels, hazardous materials, or the like. More particularly, the present invention relates to a method and devices for preventing dangerous "pull aways" that can occur when drivers refuel or reload tanks of fuel.
II. Description of the Prior Art
Propane gas is dispensed from large facilities through special valves which must be releasably coupled to delivery trucks by operators. A variety of hardware items are known in the art for coupling the fuel pipes and systems together. One persistent and dangerous problem relates to "pull aways" or "drive aways."
Propane delivery trucks are routinely refilled at a central facility. Fuel receptive fittings are mated to appropriate dispensing hoses, and when the truck is filled, safety valves are closed and the apparatus should be disconnected. Even experienced drivers may forget to disconnect the fueling valves and hoses before driving away. If the high pressure gas transfer hoses are still connected, a disaster can result. When the truck driver forgets to disconnect the fueling connection before attempting to drive away, the connection will be violently broken. Even though certain "break away" safety valves are normally employed in anticipation of the drive away problem, the hose and/or metal parts may violently snap backwards. When the broken hose forcibly slams into concrete or metallic surroundings, sparks can result. Leaking gases may easily be ignited with potentially life-threatening consequences. In the past, lives have been lost to fires and explosions proximately caused by such drive aways.
A similar problem also afflicts self service gasoline stations. When an ordinary motorist forgets to disconnect the gas pump after refueling, the hose will be broken when he drives off. When the "pull away" occurs, the hose or dispenser may snap back and injure a bystander. Worse yet, spilled gasoline may possibly ignite. At the very least the gasoline pump will be damaged, and the station owner will be subject to down time, lost revenue, and expensive repairs.
It is well known in the propane dispensing art that "pull aways" initiate accidents. Remedial actions have been proposed. At this time it is conventionally recommended that drivers remove their ignition keys and hang them on a peg board as a reminder to disconnect before driving away. Obviously this procedure is inadequate. It is often forgotten or ignored. As a result, several hundred pull-away incidents occur each year.
Finally, "pull aways" are not limited to fueling or refueling situations. They have occurred in the past in conjunction with the loading of hazardous waste trucks. Hence my inventions also have relevance in the field of hazardous waste management.